An increasing number of office workers are located in open plan offices. In such offices, but also in other instances, a common complaint is that people have difficulties in doing their job because of annoying and distracting sounds around them. The most distracting sound source in open plan offices is speech, in particular speech resulting from (informal) meetings of people. The participants to the meeting need to have a high level of speech intelligibility, while other people who are not participating in the meeting are annoyed and distracted by the (unwanted) speech.
Conventional means to reduce the distractions of speech are blocking and/or absorbing the sound with walls between the desks. This can be quite effective, but it destroys the open character of the space and the benefits that this brings with respect to collaboration of people in the open plan office. Distraction by speech may also be reduced by sound masking (adding noise). This preserves the openness of space, but it also raises the general sound level in the office.
One approach proposed by the applicant is to provide localised sound amplification, with the amplified output provided in a directional manner. In this way, local speech amplification is used, for example above a meeting table, in order to improve the audibility of a conversation in that environment, but to reduce the disturbance to the neighbouring areas. This approach enables users to speak more softly and still be heard in their localised area, by means of the amplification system. However, if the noise level does increase, the users of this system may not perceive that their conversation is becoming so loud that it is disturbing others nearby.
There are also examples of lighting system which aim to provide lighting to an area which matches the activity taking place in the area, and this activity can be detected based on the measured sound. For example, US20060071605A1 discloses a system in which the “activity” of people is measured for example using microphones, and this is used to control a light source. This is, for example, to adapt the light to a certain task. US20100194314A1 discloses that lighting can be adjusted based on measured sound to change the “atmosphere” of a space.
There can still remain a problem that the noise level introduced by people in one part of an open area is disturbing to others in a nearby area.